1. Field
The present disclosure relates generally to wireless communication system. More specifically the present disclosure related to methods and apparatus for characterized pre-distortion calibration of a power amplifier.
2. Background
Wireless communication devices have become smaller and more powerful as well as more capable. Increasingly users rely on wireless communication devices for mobile phone use as well as email and Internet access. At the same time, devices have become smaller in size. Devices such as cellular telephones, personal digital assistants (PDAs), laptop computers, and other similar devices provide reliable service with expanded coverage areas. Such devices may be referred to as mobile stations, stations, access terminals, user terminals, subscriber units, user equipments, and similar terms.
A wireless communication system may support communication for multiple wireless communication devices at the same time. In use, a wireless communication device may communicate with one or more base stations by transmissions on the uplink and downlink. Base stations may be referred to as access points, Node Bs, or other similar terms. The uplink or reverse link refers to the communication link from the wireless communication device to the base station, while the downlink or forward link refers to the communication from the base station to the wireless communication devices.
Wireless communication systems may be multiple access systems capable of supporting communication with multiple users by sharing the available system resources, such as bandwidth and transmit power. Examples of such multiple access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, wideband code division multiple access (WCDMA) systems, global system for mobile (GSM) communication systems, enhanced data rates for GSM evolution (EDGE) systems, and orthogonal frequency division multiple access (OFDMA) systems.
As use of mobile devices grows, so does the need to manufacture and test new devices in an efficient manner. Linear power amplifiers, such as those used for EDGE mode, require careful pre-distortion calibration in order to operate the power amplifier. These tests demand significant time at the factory for the calibration process. Typically, such calibration and testing requires measurement of multiple values throughout the testing process. These tests require significant amounts of time to conduct. In some cases, operating values are selected which may be less than optimum but which require less testing time to determine may be used. In these cases, operating values such as EDGE mode current are less than optimum.
There is a need in the art for methods and apparatus for characterizing pre-distortion in the calibration process with reduced number of measurements needed to determine device calibration.